Including jsLint in your validation using nAnt, batch files or AJAX

jsLint is a fantastic tool developed by Douglas Crockford, Yahoo!’s JavaScript architect which will validate JavaScript source to a strict specification which often catches hidden errors.

As the website says jsLint will probably “hurt your feelings” as it enforces conventions which not everyone would like…however, I would recommend you include it within your build scripts and work through any issues it throws up. You will be grateful of it in the end!

I am going to take you through ways to integrate jsLint in to a nAnt build process, or just be able to run it manually locally on Windows.

You can download all the example files for this post.

Setup

Download the relevant files needed and customise the jsLint.wsf defaults (line 56) to fit with your preferences. I have included a less strict version for this example.

1. Running jsLint manually

You can run jsLint manually on your js files by passing their location as the first parameter of jsLint.bat. The location can be an absolute or relative location. Here are some examples:

jsLint.bat c:\project\js\test.js

jsLint.bat ..\..\js\test.js

You may want to create another batch file which will run it on multiple files to save you having to type the locations in every time.

2. nAnt build target

You can include these tests within nAnt build scripts so that the build fails if the JavaScript doesn’t validate. Here is an example build target (download).

<target name="jsLintValidation" description="validates JS files">
  <foreach item="File" property="jsfile">
    <in>
      <items>
        <include name="${siteroot}\js\*.js" />
      </items>
    </in>
    <do>
      <exec
        program="${jslintdir}\jslint.bat"
        commandline="${jsfile}" />
    </do>
  </foreach>
</target>

3. Using AJAX within your JavaScript Unit tests

The beauty of jsLint is it is writted in JavaScript, which means that you can use the functionality within a browser. This won’t work on static sites because of security issues with XmlHttpRequests, but if your tests are on a hosted site then you can load your JavaScript using AJAX and run them through jsLint.

It’s as simple as running the JSLINT function (example, download):

var myResult = JSLINT(source, option);

If it checks out, JSLINT returns true. Otherwise, it returns false and you can inspect JSLINT.errors to find out the problems. Details of the structure of JSLINT.errors can be found within the comments of the fulljslint.js file.

Let me know how you find jsLint as a validation tool, or please feel free to ask any questions.

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Flickr : jsLint

juxtapo plugin framework…feedback wanted

I am appealing for your thoughts. You may have taken a look at juxtapo front end tools which includes an in browser templating system for overlays. It includes an API which has been designed to allow developers to extend the core functionality with plugins. I want to extend this so that juxtapo could be aware of available plugins and also plugins could communicate and be aware of each other.

Juxtapo plugins generally initiate themselves as Juxtapo does and extend the core functionality. An example of this is the QUnit plugin which allows the developer to link a number of unit tests to a particular template. It hooks in to the API and once juxtapo has initialised looks up the current template and runs the tests.

What are your thoughts on the following ways which this could be done?

1. Constructor

This method uses a Plugin constructor to create a Plugin object which could then be assigned to a variable.

juxtapo.plugins.newPlugin = new juxtapo.Plugin({
    init: function(){
        juxtapo.initComplete(function(){
            // functionality added on initConfig
        });
    },
    publicVar: 'public'
});

or

juxtapo.plugins.newPlugin = new juxtapo.Plugin(function(){
    juxtapo.initConfig(function(){
        // functionality added on initConfig
    });
    privateVar = 'private';
    return {
        init: function(){
            juxtapo.initComplete(function(){
                // functionality added on initConfig
            });
        },
        publicVar: 'public'
    };
});

2. Add Function

This method uses a function to create a plugin object with defaults and then allow you to customise it. It would then add the resulting plugin to the variable name provided by the first attribute.

juxtapo.plugins.add('newPlugin', function(){
    // this is the function to construct the plugin which has defaults
    // created already
    juxtapo.initConfig(function(){
        // functionality added on initConfig
    });
    // optional init function which would be fired by juxtapo just before
    // iniComplete
    this.init = function(){};
    this.publicVar = 'public';
});

3. Anonymous Function

This method is very open. When juxtapo initialises it will check to see if there is an init function and if it finds one it will call it, otherwise you can attach listener functions to other juxtapo events.

juxtapo.plugins.newPlugin = function(){
    juxtapo.initConfig(function(){
        // functionality added on initConfig
    });
    return {
        init: function(){},
        publicVar: 'public'
    }
}();

3. Create Plugin Function

This works in very much the same way as the add function but uses another function to return an object which can be assigned to the newPlugin variable.

juxtapo.plugins.newPlugin = juxtapo.createPlugin(function(){
    // this is the function to init the plugin which has defaults
    // created already
    juxtapo.initConfig(function(){
        // functionality added on initConfig
    });
    this.init = function(){};
    this.publicVar = 'public';
});

I will be converting the current example juxtapo plugins for the next release v0.8 to use which ever method we feel is the most intuitive and simple to develop with so your help and thoughts will be very much appreciated. If you know of any standards for framework plugins then let me know as well. Thanks in advance.

Del.icio.us : juxtapo

liScroll jQuery news ticker customisation with next/previous/play

This post has been moved to http://the-taylors.org/blog/2010/03/15/liscroll-jquery-news-ticker-customisation-with-next-previous-play/

Your Green Idea – flowers, bees and hijacking

Today is the launch of Phase 2 of ‘Your Green Idea‘, part of Marks and Spencer’s Plan A initiative to become the world’s most sustainable major retailer by 2015.

We’ve had a few challenges with this project the main one being part of the remit was to build the site so that particular links would slide elements of the current page out and elements of the new page in from either the left or right hand side of the screen. The background to the header needed to go behind the logo and the primary navigation; and the content needed to sit on top.

You can visit the Your Green Idea site at http://yourgreenidea.co.uk

Finally managed to release a beta for juxtapo

Phew, I’ve been working hard at getting unit tests done, bugs ironed out and docs written so that I can get a release of juxtapo out and now it’s here.

juxtapo is a personal project I’ve been working on which gives in browser overlays and previews for template building. It’s been so valuable to me in my day to day work that I thought I should share it out.

So take a look and let me know what you think.

Javascript development and deployment strategy – Part 1

With the popularity of JavaScript rising significantly the amount of code within one project has grown to the extent where it needs to be separated in to separate files unless you want to be scrolling through thousands of lines of code. Whether you do this per class or namespace is another debate but I have been thinking through how all these separate files might be combined appropriately and compressed at deployment.

I have decided to itemise what I would ideally want to achieve and maybe some thoughts on how i could do it.

1. I want to be able to split code in to appropriate sections so that i can save them across multiple files.
   • this will make it easier to find code
   • this will make code more modular and help to debug
2. I only want one script reference within the html file even at dev time
   • i don’t want to annoy the back end devs with the hassle of different versions of the html head area
   • i want to manage easily the order in which scripts are loaded and which scripts are grouped together.
   • i want the dev to mimic the live environment as closely as possible
3. I want a system which is flexible enough to allow me to specify which scripts get combined on deployment
   • if there are sub sections to the code which change more frequently to others i don’t want the client to have to download the full whack when something small has changed
4. I want this to be extremely painless to implement
   • pain is not that desirable to me

With these four requirements in mind I set about my strategy and have come up with this:

1. a root file for each set which at dev time dynamically adds the linked files to the page
2. You can have as many root files as you want and you only need to maintain one list of links within each root file.
3. It only takes 3 very simple steps:
   1. copy and paste short section of standalone code in to a root file
   2. set the root file js name
   3. include a list of files which will be combined on deployment

In part 2 I will give a demonstration of this in action.